1. Field of the Invention
This application is based upon and claims the benefit of the priority of Japanese patent application No. 2011-111673, filed on May 8, 2011, the disclosure of which is incorporated herein in its entirety by reference thereto.
The present disclosure relates to a semiconductor device having a detection test structure for a crack of a semiconductor chip (or chip crack detection structure).
2. Description of Related Art
In manufacture of a semiconductor device, a stress or the like on cutting, mounting or heating sometimes causes a crack in a semiconductor chip. As a method of detecting such a crack, there is an example using a structure disclosed by Japanese Patent Kokai Publication No. H06-244254 (Patent Document 1), for example. This detects existence of the crack by measuring resistance of an electric conductor provided in a periphery of the semiconductor chip.
Japanese Patent Kokai Publication No. 2009-54862A, which corresponds to US2009/057925A1 (Patent Document 2) discloses an art of detecting whether or not there is a crack in a semiconductor chip by providing a wiring and a plurality of electrode pads for detecting the crack along an entire periphery of the semiconductor chip and detecting change of resistance between the electrode pads which are selected among the plurality of the electrode pads and connected to both ends of the wiring.
The above Patent Documents are incorporated herein by reference thereto in their entirety. The inventor has realized that in the detection methods disclosed in Patent Documents 1 and 2, no consideration is given to a detection of a crack of each semiconductor chip in a semiconductor device of a stack type in which a plurality of the semiconductor chips are stacked. If a plurality of the semiconductor chips disclosed in Patent Document 2 are stacked, in the semiconductor device of the stack type, the pads for detecting a crack are connected in common. Therefore, even though the occurrence of a crack in any semiconductor chip of the semiconductor device of the stack type can be confirmed, there is a problem that the semiconductor chip having the crack can not be identified.
The inventor has realized that if the structure disclosed in Patent Document 1 is used for the semiconductor device of the stack type, even though semiconductor chips having an electric conductor 70 for crack detection shown in FIG. 12B are stacked, the crack in the most exterior semiconductor chip (Slice 0) shown in FIG. 12A may be detected, but the crack in interior semiconductor chips can not be detected.